Atlantic Envelope stocks a wide variety of Booklet Envelopes. Booklet Envelopes have a large uninterrupted printing area, great for getting your promotions noticed. Our Booklet Envelopes are a cost effective way of mailing annual reports, brochures, direct mail promotions, sales literature & announcements.. Atlantic Envelopes Booklet Envelopes open side/side seam construction allow for easy automatic insertion.